ac recharge/conversion question
Thread Starter
Racer
Joined: Aug 2006
Posts: 493
Likes: 1
From: yarmouth ma
ac recharge/conversion question
ok, bought the kit from autozone. i put on the new valves and started to charge system. the pressure was way too high so i stopped. the system was taking in the freon, but the return line was as cold as the other line. my neighbor who is a mechanic said i have a blockage on the high side line. he suggested its the dryer. the ac in this car has not been used in years and there was no r12 in it. he thinks the dryer is blocked and full of junk so that is causing the high pressure.
so would you guys agree its the dryer or do you think it could be something else? I am selling the car and I don't want to replace every piece of this system, here in new england we only use the ac for a few months anyway.
thanks
so would you guys agree its the dryer or do you think it could be something else? I am selling the car and I don't want to replace every piece of this system, here in new england we only use the ac for a few months anyway.
thanks
Drifting
Joined: Jan 2004
Posts: 1,991
Likes: 3
From: Piscataway NJ
This will cost ya to get it right. Sell it as is.
Find your leak first or you are wasting time and money
Dryer should be changed
Change all o rings
System flush
New orfice tube
Add 134 oil
Evacuate the system
Hope for the best
Find your leak first or you are wasting time and money
Dryer should be changed
Change all o rings
System flush
New orfice tube
Add 134 oil
Evacuate the system
Hope for the best
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Replace the dryer and orfice tube. NEVER try to re-do an a/c system without replacing these. You are asking for problems, which you found. Sounds like the dryer was saturated with moisture from the empty/unsealed system. Working a/c will generally be worth the repair cost at resale.
Burning Brakes
Joined: Jun 2005
Posts: 764
Likes: 2
From: THE OLDER I GET THE BETTER I WAS! NORTHERN ONTARIO
[QUOTE=markdtn;1566931526]Replace the dryer and orfice tube. NEVER try to re-do an a/c system without replacing these.
I did this with my 79 recharged it...works fine. Make sure you evacuate the system.
I did this with my 79 recharged it...works fine. Make sure you evacuate the system.
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Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Flush the system! Replace the dryer and install a blue (ford) orifice. Add the correct amount of 134 compatible oil, after pulling a vacuum and charge it with 10% less 134 than you would with R-12.
Le Mans Master
Joined: Jun 2006
Posts: 6,400
Likes: 1,226
From: Tampa Florida
Tools of the Trade
Last edited by 71 Green 454; Sep 2, 2008 at 04:56 PM.
Burning Brakes
Joined: Apr 2008
Posts: 945
Likes: 1
Doesn't today's R134a refrigerant cans come with the correct amount of oil in the can along with the refrigerant? Other than putting a little oil in the compressor to lube it if you are replacing the compressor do you really need to add oil separately?
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I know that R-12 came with the lubricant already in the can...I don't know about R-134, but I would guess that it did. [nothing on the can about it?]
It doesn't sound like you vacuumed the system down. With luck, you only froze up the coils until you turned it off. Not sucking the system down has caused compressors to lock up...permanently.
It doesn't sound like you vacuumed the system down. With luck, you only froze up the coils until you turned it off. Not sucking the system down has caused compressors to lock up...permanently.
Race Director
Joined: Jul 2004
Posts: 12,708
Likes: 329
From: Scottsdale Arizona
I found the vacuum pump to be good for leak detection as well. Once you've evacuated the sytem for long enough to remove the moisture, you shut off the valve and let it sit with the pump off. If the level of vacuum changes, you have a leak. Listening for the hiss should help locate all but the smallest.
Burning Brakes
Joined: Apr 2008
Posts: 945
Likes: 1
I've never done anything like this before but I have some confidence now after reading a lot of very useful info from all these helpful CF bros.
http://cgi.ebay.com/ebaymotors/New-A...=p4506.c0.m245
Last edited by Bobz08C6; Sep 4, 2008 at 03:27 PM.
Racer
Joined: Feb 2007
Posts: 457
Likes: 2
From: Tucson Arizona
The gauge set looks ok, not sure about the pump, though. I have never used on that small before.
R134 may come with lubricant, its ok to top off, but to replace componants and recharge, I wouldn't do it myself.
If you are just doing the dryer and expansion valve, its probably ok.
If you are converting from R12 to R134a you need to change all the oil in the system, otherwise you are asking for trouble. The older R12 oil will not be compatable with the 134a. You also have to be careful, because some of the older componants in the system may not be compatable either.
You also must have gauges to get the 134a charge right, because the site glass alone will not be a good indicator for the 134a.
R134 may come with lubricant, its ok to top off, but to replace componants and recharge, I wouldn't do it myself.
If you are just doing the dryer and expansion valve, its probably ok.
If you are converting from R12 to R134a you need to change all the oil in the system, otherwise you are asking for trouble. The older R12 oil will not be compatable with the 134a. You also have to be careful, because some of the older componants in the system may not be compatable either.
You also must have gauges to get the 134a charge right, because the site glass alone will not be a good indicator for the 134a.
Burning Brakes
Joined: Oct 2001
Posts: 911
Likes: 5
From: TN
expansion valve
capecorvette I do not know the specifics of your 1979's A/C system, however my 70 A/C has an expansion valve and the line connecting to the expansion valve coming from the condenser has a small metal screen/filter in the expansion valve connection. If a dryers desiccant bag/container has leaked desiccant it will travel to the expansion valve and stop the flow of R12 or R134. It happened to my 70 in 1988. GM dealership mechanics could not find the problem, I did by reading my service manual.
Last edited by 70ZZ3 96LT4; Sep 5, 2008 at 09:11 AM.